Thursday, July 3, 2008

9.1 Shrimp's auntie

No, this is not a cockroach. It is a mantis shrimp (shown above is one of the less colorful varieties), also known as 蝦姑 (the shrimp's auntie) in Chinese.

A more colorful one is shown below:It is more a crab than a shrimp. The taste is rather bland, though - probably the reason why it has never made it into the menu of Chinese restaurants. The Italians do have a way of preparing it (recipe below quoted from here):

Lightly oil a deep skillet large enough to contain all the shrimp, and lay them flat in it with the garlic and a pinch of salt. Sprinkle a little water over the shrimp, cover the skillet with a wet cloth, and cook over very high heat for 2-3 minutes. Serve the shrimp at once, garnished with sprigs of parsley and, if you like, lemon wedges.

Note: It goes without saying that it'll be a messy sitting, as the shrimp shell is a bit hard to crack.

There are always people who look at the shrimp differently. A few have noticed the unusual eyes:And a close-up (by Roy Campbell, from www.wired.com):In the 3/20/2008 issue of Current Biology, Cronin, Marshall, and Caldwell reported that the mantis shrimp had a 4th mode of vision. Really, unlike everybody else, it sees circular polarization light. (Note: the other three modes of vision: black & white, color, and linear polarization). So what does that mean? Let's look at the polarization process first (below quoted from here).

"Light in the form of a plane wave in space is said to be linearly polarized...If light is composed of two plane waves of equal amplitude by differing in phase by 90°, then the light is said to be circularly polarized. If two plane waves of differing amplitude are related in phase by 90°, or if the relative phase is other than 90° then the light is said to be elliptically polarized."

In other words, if one can see the tip of the vector, circularly (or elliptically) polarized light would appear to rotate. It can be produced by passing linearly polarized light through a quarter-wave plate at a 45° angle to the optic axis of the plate. For the transmission of electromagnetic waves, circular polarization has almost no signal loss. It will be a great way of cell phone communication - no more dropped signals. Of course, for the mantis shrimp, this "technology" has been in use for more than 400 million years. Human electrical engineers are still yet to catch up.

It is fair to assume that the mantis shrimp uses circularly polarized light to communicate for mating and/or staking territorial claims - as in other animals. Its shell then must be the source of the reflected polarization light. Its compound eyes already contain thousands of rows of light-detecting units called ommatidia - a mix of photoreceptors and filters.

If you think about it, the mantis shrimp will survive long pass other species on earth: It looks un-appetizing, in fact, not much taste, has a hard shell for protection, and communicates with polarized light which no one else can see. Not bad at all. In fact, it is also known as the shrimp from Mars.

...the mantis shrimp had a 4th mode of vision.My eye opening is about the above statement not about food; their popping eyes look more like Boston lobster than shrimp to me. Do Boston lobsters have 4th mode of vision too? Is that only unique to Mantis shrimp?I've since watched a few You Tube videos about this creature. Very interesting to watch indeed. Some also call them Peacock shrimp for its colorful display.

Boston lobsters? Actually, they are Maine lobsters - the ones with two large claws which are absent from the Pacific lobsters.

Lobster eyes have a different design from that of the mantis shrimp. In fact, the optics in the former has been used to create the Lobster Eye X-ray Imaging Device now used by Homeland Security. And as stated in the post, the mantis shrimp optics can be used for more coherent electromagnetic wave transmission. Implication: their visual modes are different. The 4th mode of vision is quite unusual; although no one knows whether only the mantis shrimp has it.

Mantis shrimps are a successful species found world-wide and are called by different names by the locals. For example, it is also known as 蝦猴 (shrimp monkey) for reasons unknown.